Yikes...
Are you using the RBA or the replaceable stock coils?
I'll be honest, washing a coil is pretty much guaranteed to wreck it.
My advice, buy a new coil for your tank.
Clean and dry your tank thoroughly using only water and start fresh, it may take a tank or so to completely rid yourself of the menthol taste but it's probably your best bet.
When swapping between flavours in the same tank I always try and keep to something similar, I.e strawberry to cherry.
Good luck